xref: /openbsd-src/usr.bin/ssh/monitor_wrap.c (revision aa997e528a848ca5596493c2a801bdd6fb26ae61)
1 /* $OpenBSD: monitor_wrap.c,v 1.99 2018/03/03 03:15:51 djm Exp $ */
2 /*
3  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
4  * Copyright 2002 Markus Friedl <markus@openbsd.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26  */
27 
28 #include <sys/types.h>
29 #include <sys/uio.h>
30 #include <sys/queue.h>
31 
32 #include <errno.h>
33 #include <pwd.h>
34 #include <signal.h>
35 #include <stdio.h>
36 #include <string.h>
37 #include <unistd.h>
38 
39 #ifdef WITH_OPENSSL
40 #include <openssl/bn.h>
41 #include <openssl/dh.h>
42 #endif
43 
44 #include "xmalloc.h"
45 #include "ssh.h"
46 #ifdef WITH_OPENSSL
47 #include "dh.h"
48 #endif
49 #include "buffer.h"
50 #include "key.h"
51 #include "cipher.h"
52 #include "kex.h"
53 #include "hostfile.h"
54 #include "auth.h"
55 #include "auth-options.h"
56 #include "packet.h"
57 #include "mac.h"
58 #include "log.h"
59 #include <zlib.h>
60 #include "monitor.h"
61 #ifdef GSSAPI
62 #include "ssh-gss.h"
63 #endif
64 #include "monitor_wrap.h"
65 #include "atomicio.h"
66 #include "monitor_fdpass.h"
67 #include "misc.h"
68 
69 #include "channels.h"
70 #include "session.h"
71 #include "servconf.h"
72 
73 #include "ssherr.h"
74 
75 /* Imports */
76 extern z_stream incoming_stream;
77 extern z_stream outgoing_stream;
78 extern struct monitor *pmonitor;
79 extern Buffer loginmsg;
80 extern ServerOptions options;
81 
82 void
83 mm_log_handler(LogLevel level, const char *msg, void *ctx)
84 {
85 	Buffer log_msg;
86 	struct monitor *mon = (struct monitor *)ctx;
87 
88 	if (mon->m_log_sendfd == -1)
89 		fatal("%s: no log channel", __func__);
90 
91 	buffer_init(&log_msg);
92 	/*
93 	 * Placeholder for packet length. Will be filled in with the actual
94 	 * packet length once the packet has been constucted. This saves
95 	 * fragile math.
96 	 */
97 	buffer_put_int(&log_msg, 0);
98 
99 	buffer_put_int(&log_msg, level);
100 	buffer_put_cstring(&log_msg, msg);
101 	put_u32(buffer_ptr(&log_msg), buffer_len(&log_msg) - 4);
102 	if (atomicio(vwrite, mon->m_log_sendfd, buffer_ptr(&log_msg),
103 	    buffer_len(&log_msg)) != buffer_len(&log_msg))
104 		fatal("%s: write: %s", __func__, strerror(errno));
105 	buffer_free(&log_msg);
106 }
107 
108 int
109 mm_is_monitor(void)
110 {
111 	/*
112 	 * m_pid is only set in the privileged part, and
113 	 * points to the unprivileged child.
114 	 */
115 	return (pmonitor && pmonitor->m_pid > 0);
116 }
117 
118 void
119 mm_request_send(int sock, enum monitor_reqtype type, Buffer *m)
120 {
121 	u_int mlen = buffer_len(m);
122 	u_char buf[5];
123 
124 	debug3("%s entering: type %d", __func__, type);
125 
126 	put_u32(buf, mlen + 1);
127 	buf[4] = (u_char) type;		/* 1st byte of payload is mesg-type */
128 	if (atomicio(vwrite, sock, buf, sizeof(buf)) != sizeof(buf))
129 		fatal("%s: write: %s", __func__, strerror(errno));
130 	if (atomicio(vwrite, sock, buffer_ptr(m), mlen) != mlen)
131 		fatal("%s: write: %s", __func__, strerror(errno));
132 }
133 
134 void
135 mm_request_receive(int sock, Buffer *m)
136 {
137 	u_char buf[4];
138 	u_int msg_len;
139 
140 	debug3("%s entering", __func__);
141 
142 	if (atomicio(read, sock, buf, sizeof(buf)) != sizeof(buf)) {
143 		if (errno == EPIPE)
144 			cleanup_exit(255);
145 		fatal("%s: read: %s", __func__, strerror(errno));
146 	}
147 	msg_len = get_u32(buf);
148 	if (msg_len > 256 * 1024)
149 		fatal("%s: read: bad msg_len %d", __func__, msg_len);
150 	buffer_clear(m);
151 	buffer_append_space(m, msg_len);
152 	if (atomicio(read, sock, buffer_ptr(m), msg_len) != msg_len)
153 		fatal("%s: read: %s", __func__, strerror(errno));
154 }
155 
156 void
157 mm_request_receive_expect(int sock, enum monitor_reqtype type, Buffer *m)
158 {
159 	u_char rtype;
160 
161 	debug3("%s entering: type %d", __func__, type);
162 
163 	mm_request_receive(sock, m);
164 	rtype = buffer_get_char(m);
165 	if (rtype != type)
166 		fatal("%s: read: rtype %d != type %d", __func__,
167 		    rtype, type);
168 }
169 
170 #ifdef WITH_OPENSSL
171 DH *
172 mm_choose_dh(int min, int nbits, int max)
173 {
174 	BIGNUM *p, *g;
175 	int success = 0;
176 	Buffer m;
177 
178 	buffer_init(&m);
179 	buffer_put_int(&m, min);
180 	buffer_put_int(&m, nbits);
181 	buffer_put_int(&m, max);
182 
183 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_MODULI, &m);
184 
185 	debug3("%s: waiting for MONITOR_ANS_MODULI", __func__);
186 	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_MODULI, &m);
187 
188 	success = buffer_get_char(&m);
189 	if (success == 0)
190 		fatal("%s: MONITOR_ANS_MODULI failed", __func__);
191 
192 	if ((p = BN_new()) == NULL)
193 		fatal("%s: BN_new failed", __func__);
194 	if ((g = BN_new()) == NULL)
195 		fatal("%s: BN_new failed", __func__);
196 	buffer_get_bignum2(&m, p);
197 	buffer_get_bignum2(&m, g);
198 
199 	debug3("%s: remaining %d", __func__, buffer_len(&m));
200 	buffer_free(&m);
201 
202 	return (dh_new_group(g, p));
203 }
204 #endif
205 
206 int
207 mm_key_sign(struct sshkey *key, u_char **sigp, u_int *lenp,
208     const u_char *data, u_int datalen, const char *hostkey_alg)
209 {
210 	struct kex *kex = *pmonitor->m_pkex;
211 	Buffer m;
212 
213 	debug3("%s entering", __func__);
214 
215 	buffer_init(&m);
216 	buffer_put_int(&m, kex->host_key_index(key, 0, active_state));
217 	buffer_put_string(&m, data, datalen);
218 	buffer_put_cstring(&m, hostkey_alg);
219 
220 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_SIGN, &m);
221 
222 	debug3("%s: waiting for MONITOR_ANS_SIGN", __func__);
223 	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_SIGN, &m);
224 	*sigp  = buffer_get_string(&m, lenp);
225 	buffer_free(&m);
226 
227 	return (0);
228 }
229 
230 struct passwd *
231 mm_getpwnamallow(const char *username)
232 {
233 	struct ssh *ssh = active_state;		/* XXX */
234 	Buffer m;
235 	struct passwd *pw;
236 	u_int len, i;
237 	ServerOptions *newopts;
238 
239 	debug3("%s entering", __func__);
240 
241 	buffer_init(&m);
242 	buffer_put_cstring(&m, username);
243 
244 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PWNAM, &m);
245 
246 	debug3("%s: waiting for MONITOR_ANS_PWNAM", __func__);
247 	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_PWNAM, &m);
248 
249 	if (buffer_get_char(&m) == 0) {
250 		pw = NULL;
251 		goto out;
252 	}
253 	pw = buffer_get_string(&m, &len);
254 	if (len != sizeof(struct passwd))
255 		fatal("%s: struct passwd size mismatch", __func__);
256 	pw->pw_name = buffer_get_string(&m, NULL);
257 	pw->pw_passwd = buffer_get_string(&m, NULL);
258 	pw->pw_gecos = buffer_get_string(&m, NULL);
259 	pw->pw_class = buffer_get_string(&m, NULL);
260 	pw->pw_dir = buffer_get_string(&m, NULL);
261 	pw->pw_shell = buffer_get_string(&m, NULL);
262 
263 out:
264 	/* copy options block as a Match directive may have changed some */
265 	newopts = buffer_get_string(&m, &len);
266 	if (len != sizeof(*newopts))
267 		fatal("%s: option block size mismatch", __func__);
268 
269 #define M_CP_STROPT(x) do { \
270 		if (newopts->x != NULL) \
271 			newopts->x = buffer_get_string(&m, NULL); \
272 	} while (0)
273 #define M_CP_STRARRAYOPT(x, nx) do { \
274 		newopts->x = newopts->nx == 0 ? \
275 		    NULL : xcalloc(newopts->nx, sizeof(*newopts->x)); \
276 		for (i = 0; i < newopts->nx; i++) \
277 			newopts->x[i] = buffer_get_string(&m, NULL); \
278 	} while (0)
279 	/* See comment in servconf.h */
280 	COPY_MATCH_STRING_OPTS();
281 #undef M_CP_STROPT
282 #undef M_CP_STRARRAYOPT
283 
284 	copy_set_server_options(&options, newopts, 1);
285 	log_change_level(options.log_level);
286 	process_permitopen(ssh, &options);
287 	free(newopts);
288 
289 	buffer_free(&m);
290 
291 	return (pw);
292 }
293 
294 char *
295 mm_auth2_read_banner(void)
296 {
297 	Buffer m;
298 	char *banner;
299 
300 	debug3("%s entering", __func__);
301 
302 	buffer_init(&m);
303 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTH2_READ_BANNER, &m);
304 	buffer_clear(&m);
305 
306 	mm_request_receive_expect(pmonitor->m_recvfd,
307 	    MONITOR_ANS_AUTH2_READ_BANNER, &m);
308 	banner = buffer_get_string(&m, NULL);
309 	buffer_free(&m);
310 
311 	/* treat empty banner as missing banner */
312 	if (strlen(banner) == 0) {
313 		free(banner);
314 		banner = NULL;
315 	}
316 	return (banner);
317 }
318 
319 /* Inform the privileged process about service and style */
320 
321 void
322 mm_inform_authserv(char *service, char *style)
323 {
324 	Buffer m;
325 
326 	debug3("%s entering", __func__);
327 
328 	buffer_init(&m);
329 	buffer_put_cstring(&m, service);
330 	buffer_put_cstring(&m, style ? style : "");
331 
332 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTHSERV, &m);
333 
334 	buffer_free(&m);
335 }
336 
337 /* Do the password authentication */
338 int
339 mm_auth_password(struct ssh *ssh, char *password)
340 {
341 	Buffer m;
342 	int authenticated = 0;
343 
344 	debug3("%s entering", __func__);
345 
346 	buffer_init(&m);
347 	buffer_put_cstring(&m, password);
348 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTHPASSWORD, &m);
349 
350 	debug3("%s: waiting for MONITOR_ANS_AUTHPASSWORD", __func__);
351 	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_AUTHPASSWORD, &m);
352 
353 	authenticated = buffer_get_int(&m);
354 
355 	buffer_free(&m);
356 
357 	debug3("%s: user %sauthenticated",
358 	    __func__, authenticated ? "" : "not ");
359 	return (authenticated);
360 }
361 
362 int
363 mm_user_key_allowed(struct ssh *ssh, struct passwd *pw, struct sshkey *key,
364     int pubkey_auth_attempt, struct sshauthopt **authoptp)
365 {
366 	return (mm_key_allowed(MM_USERKEY, NULL, NULL, key,
367 	    pubkey_auth_attempt, authoptp));
368 }
369 
370 int
371 mm_hostbased_key_allowed(struct passwd *pw, const char *user, const char *host,
372     struct sshkey *key)
373 {
374 	return (mm_key_allowed(MM_HOSTKEY, user, host, key, 0, NULL));
375 }
376 
377 int
378 mm_key_allowed(enum mm_keytype type, const char *user, const char *host,
379     struct sshkey *key, int pubkey_auth_attempt, struct sshauthopt **authoptp)
380 {
381 	Buffer m;
382 	u_char *blob;
383 	u_int len;
384 	int r, allowed = 0;
385 	struct sshauthopt *opts = NULL;
386 
387 	debug3("%s entering", __func__);
388 
389 	if (authoptp != NULL)
390 		*authoptp = NULL;
391 
392 	/* Convert the key to a blob and the pass it over */
393 	if (!key_to_blob(key, &blob, &len))
394 		return 0;
395 
396 	buffer_init(&m);
397 	buffer_put_int(&m, type);
398 	buffer_put_cstring(&m, user ? user : "");
399 	buffer_put_cstring(&m, host ? host : "");
400 	buffer_put_string(&m, blob, len);
401 	buffer_put_int(&m, pubkey_auth_attempt);
402 	free(blob);
403 
404 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_KEYALLOWED, &m);
405 
406 	debug3("%s: waiting for MONITOR_ANS_KEYALLOWED", __func__);
407 	mm_request_receive_expect(pmonitor->m_recvfd,
408 	    MONITOR_ANS_KEYALLOWED, &m);
409 
410 	allowed = buffer_get_int(&m);
411 	if (allowed && type == MM_USERKEY) {
412 		if ((r = sshauthopt_deserialise(&m, &opts)) != 0)
413 			fatal("%s: sshauthopt_deserialise: %s",
414 			    __func__, ssh_err(r));
415 	}
416 	buffer_free(&m);
417 
418 	if (authoptp != NULL) {
419 		*authoptp = opts;
420 		opts = NULL;
421 	}
422 	sshauthopt_free(opts);
423 
424 	return allowed;
425 }
426 
427 /*
428  * This key verify needs to send the key type along, because the
429  * privileged parent makes the decision if the key is allowed
430  * for authentication.
431  */
432 
433 int
434 mm_sshkey_verify(const struct sshkey *key, const u_char *sig, size_t siglen,
435     const u_char *data, size_t datalen, const char *sigalg, u_int compat)
436 {
437 	Buffer m;
438 	u_char *blob;
439 	u_int len;
440 	u_int encoded_ret = 0;
441 
442 	debug3("%s entering", __func__);
443 
444 	/* Convert the key to a blob and the pass it over */
445 	if (!key_to_blob(key, &blob, &len))
446 		return (0);
447 
448 	buffer_init(&m);
449 	buffer_put_string(&m, blob, len);
450 	buffer_put_string(&m, sig, siglen);
451 	buffer_put_string(&m, data, datalen);
452 	buffer_put_cstring(&m, sigalg == NULL ? "" : sigalg);
453 	free(blob);
454 
455 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_KEYVERIFY, &m);
456 
457 	debug3("%s: waiting for MONITOR_ANS_KEYVERIFY", __func__);
458 	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_KEYVERIFY, &m);
459 
460 	encoded_ret = buffer_get_int(&m);
461 
462 	buffer_free(&m);
463 
464 	if (encoded_ret != 0)
465 		return SSH_ERR_SIGNATURE_INVALID;
466 	return 0;
467 }
468 
469 void
470 mm_send_keystate(struct monitor *monitor)
471 {
472 	struct ssh *ssh = active_state;		/* XXX */
473 	struct sshbuf *m;
474 	int r;
475 
476 	if ((m = sshbuf_new()) == NULL)
477 		fatal("%s: sshbuf_new failed", __func__);
478 	if ((r = ssh_packet_get_state(ssh, m)) != 0)
479 		fatal("%s: get_state failed: %s",
480 		    __func__, ssh_err(r));
481 	mm_request_send(monitor->m_recvfd, MONITOR_REQ_KEYEXPORT, m);
482 	debug3("%s: Finished sending state", __func__);
483 	sshbuf_free(m);
484 }
485 
486 int
487 mm_pty_allocate(int *ptyfd, int *ttyfd, char *namebuf, size_t namebuflen)
488 {
489 	Buffer m;
490 	char *p, *msg;
491 	int success = 0, tmp1 = -1, tmp2 = -1;
492 
493 	/* Kludge: ensure there are fds free to receive the pty/tty */
494 	if ((tmp1 = dup(pmonitor->m_recvfd)) == -1 ||
495 	    (tmp2 = dup(pmonitor->m_recvfd)) == -1) {
496 		error("%s: cannot allocate fds for pty", __func__);
497 		if (tmp1 > 0)
498 			close(tmp1);
499 		if (tmp2 > 0)
500 			close(tmp2);
501 		return 0;
502 	}
503 	close(tmp1);
504 	close(tmp2);
505 
506 	buffer_init(&m);
507 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PTY, &m);
508 
509 	debug3("%s: waiting for MONITOR_ANS_PTY", __func__);
510 	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_PTY, &m);
511 
512 	success = buffer_get_int(&m);
513 	if (success == 0) {
514 		debug3("%s: pty alloc failed", __func__);
515 		buffer_free(&m);
516 		return (0);
517 	}
518 	p = buffer_get_string(&m, NULL);
519 	msg = buffer_get_string(&m, NULL);
520 	buffer_free(&m);
521 
522 	strlcpy(namebuf, p, namebuflen); /* Possible truncation */
523 	free(p);
524 
525 	buffer_append(&loginmsg, msg, strlen(msg));
526 	free(msg);
527 
528 	if ((*ptyfd = mm_receive_fd(pmonitor->m_recvfd)) == -1 ||
529 	    (*ttyfd = mm_receive_fd(pmonitor->m_recvfd)) == -1)
530 		fatal("%s: receive fds failed", __func__);
531 
532 	/* Success */
533 	return (1);
534 }
535 
536 void
537 mm_session_pty_cleanup2(Session *s)
538 {
539 	Buffer m;
540 
541 	if (s->ttyfd == -1)
542 		return;
543 	buffer_init(&m);
544 	buffer_put_cstring(&m, s->tty);
545 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PTYCLEANUP, &m);
546 	buffer_free(&m);
547 
548 	/* closed dup'ed master */
549 	if (s->ptymaster != -1 && close(s->ptymaster) < 0)
550 		error("close(s->ptymaster/%d): %s",
551 		    s->ptymaster, strerror(errno));
552 
553 	/* unlink pty from session */
554 	s->ttyfd = -1;
555 }
556 
557 /* Request process termination */
558 
559 void
560 mm_terminate(void)
561 {
562 	Buffer m;
563 
564 	buffer_init(&m);
565 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_TERM, &m);
566 	buffer_free(&m);
567 }
568 
569 static void
570 mm_chall_setup(char **name, char **infotxt, u_int *numprompts,
571     char ***prompts, u_int **echo_on)
572 {
573 	*name = xstrdup("");
574 	*infotxt = xstrdup("");
575 	*numprompts = 1;
576 	*prompts = xcalloc(*numprompts, sizeof(char *));
577 	*echo_on = xcalloc(*numprompts, sizeof(u_int));
578 	(*echo_on)[0] = 0;
579 }
580 
581 int
582 mm_bsdauth_query(void *ctx, char **name, char **infotxt,
583    u_int *numprompts, char ***prompts, u_int **echo_on)
584 {
585 	Buffer m;
586 	u_int success;
587 	char *challenge;
588 
589 	debug3("%s: entering", __func__);
590 
591 	buffer_init(&m);
592 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_BSDAUTHQUERY, &m);
593 
594 	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_BSDAUTHQUERY,
595 	    &m);
596 	success = buffer_get_int(&m);
597 	if (success == 0) {
598 		debug3("%s: no challenge", __func__);
599 		buffer_free(&m);
600 		return (-1);
601 	}
602 
603 	/* Get the challenge, and format the response */
604 	challenge  = buffer_get_string(&m, NULL);
605 	buffer_free(&m);
606 
607 	mm_chall_setup(name, infotxt, numprompts, prompts, echo_on);
608 	(*prompts)[0] = challenge;
609 
610 	debug3("%s: received challenge: %s", __func__, challenge);
611 
612 	return (0);
613 }
614 
615 int
616 mm_bsdauth_respond(void *ctx, u_int numresponses, char **responses)
617 {
618 	Buffer m;
619 	int authok;
620 
621 	debug3("%s: entering", __func__);
622 	if (numresponses != 1)
623 		return (-1);
624 
625 	buffer_init(&m);
626 	buffer_put_cstring(&m, responses[0]);
627 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_BSDAUTHRESPOND, &m);
628 
629 	mm_request_receive_expect(pmonitor->m_recvfd,
630 	    MONITOR_ANS_BSDAUTHRESPOND, &m);
631 
632 	authok = buffer_get_int(&m);
633 	buffer_free(&m);
634 
635 	return ((authok == 0) ? -1 : 0);
636 }
637 
638 #ifdef GSSAPI
639 OM_uint32
640 mm_ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID goid)
641 {
642 	Buffer m;
643 	OM_uint32 major;
644 
645 	/* Client doesn't get to see the context */
646 	*ctx = NULL;
647 
648 	buffer_init(&m);
649 	buffer_put_string(&m, goid->elements, goid->length);
650 
651 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSSETUP, &m);
652 	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSSETUP, &m);
653 
654 	major = buffer_get_int(&m);
655 
656 	buffer_free(&m);
657 	return (major);
658 }
659 
660 OM_uint32
661 mm_ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *in,
662     gss_buffer_desc *out, OM_uint32 *flags)
663 {
664 	Buffer m;
665 	OM_uint32 major;
666 	u_int len;
667 
668 	buffer_init(&m);
669 	buffer_put_string(&m, in->value, in->length);
670 
671 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSSTEP, &m);
672 	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSSTEP, &m);
673 
674 	major = buffer_get_int(&m);
675 	out->value = buffer_get_string(&m, &len);
676 	out->length = len;
677 	if (flags)
678 		*flags = buffer_get_int(&m);
679 
680 	buffer_free(&m);
681 
682 	return (major);
683 }
684 
685 OM_uint32
686 mm_ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
687 {
688 	Buffer m;
689 	OM_uint32 major;
690 
691 	buffer_init(&m);
692 	buffer_put_string(&m, gssbuf->value, gssbuf->length);
693 	buffer_put_string(&m, gssmic->value, gssmic->length);
694 
695 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSCHECKMIC, &m);
696 	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSCHECKMIC,
697 	    &m);
698 
699 	major = buffer_get_int(&m);
700 	buffer_free(&m);
701 	return(major);
702 }
703 
704 int
705 mm_ssh_gssapi_userok(char *user)
706 {
707 	Buffer m;
708 	int authenticated = 0;
709 
710 	buffer_init(&m);
711 
712 	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSUSEROK, &m);
713 	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSUSEROK,
714 				  &m);
715 
716 	authenticated = buffer_get_int(&m);
717 
718 	buffer_free(&m);
719 	debug3("%s: user %sauthenticated",__func__, authenticated ? "" : "not ");
720 	return (authenticated);
721 }
722 #endif /* GSSAPI */
723 
724